On 12/04/14 18:37, Ronald Held wrote: > A CSAC does not use magnetic field as a Cs primary frequency standard > does, AFAIK. http://scpnt.stanford.edu/pnt/PNT11/2011_presentation_files/18_Lutwak-PNT2011.pdf See page 20 where the C-field coil is depicted. I was quite sure it was there. Cheers, Magnus